Using Google adword

Just a curious question. When you go to a web site and see Goggle ad words do you click on one or two to help make the web master a little money? If not why not? I personally do, because I run them on my site. in the year ive been running them ive never made any money because nobody ever clicks. So if your one of those who don't why not? Not trying to start a fight or anything just want to know what people perceptions are about the whole ad word thing.